1. Field of the Invention
This invention relates to an electron gun supporting member supporting an electron gun enclosed in a cathode ray tube of, for example, a television receiver or a terminal display apparatus.
2. Description of the Prior Art
Referring to FIG. 4, an electron gun 51, enclosed in a cathode ray tube of, for example, a television receiver or a terminal display apparatus, is assembled by having its plural electrodes, that is, a first grid G.sub.1, a second grid G.sub.2, a third grid G.sub.3 and a fourth grid G.sub.4, secured at predetermined intervals to a glass supporting rod, not shown, and is supported with respect to a neck part 53a of the cathode ray tube 53 by plural spring conductors 52 secured to the last electrode, that is the fourth grid G.sub.4.
The spring conductors 52 supporting the electron gun 51 are bent elastically deformable metal conductors mounted on a terminal part of the fourth grid G.sub.4 as the last electrode. That is, each spring conductor 54 has its distal end part 52a welded to the lateral side of the fourth grid G.sub.4 while having its bent part 52b kept in pressure contact with an electrically conductive film 54, formed of carbon particles, on the inner wall surface of the cathode ray tube 53. It is under the force of bias exerted by the spring conductors 54 that the electron gun 51 is supported with respect to the cathode ray tube 53.
The spring conductors 52 have two functions, namely the function of supporting the electron gun 51 with respect to the cathode ray tube 53 by being pressed into contact with the electrically conductive film 54 and the function of supplying a high electrical voltage supplied from an anode button 55 to the fourth grid G.sub.4 through the electrically conductive film 54. Consequently, not only a large force of bias sufficient to stably support the electron gun 51 against vibrations but also electrical conductivity to achieve electrical conduction, is required of the spring conductors.
In consideration that the spring conductors 52 are required to perform these two functions, the spring conductors 52 need to be provided at an area of the cathode ray tube which is provided with the electrically conductive film 54 and which lies ahead of the foremost part of the fourth grid G.sub.4 in the inserting direction of the electron gun for establishing electrical connection thereof with the electrically conductive film 54. For this reason, when the electron gun 51 is inserted into the cathode ray tube 53, the spring conductors exhibiting a larger force of bias has to be slidingly contacted with the electrically conductive film 54 over a longer distance. The result is that the carbon particles of the electrically conductive film 54 are rubbed and scaled off by the spring conductors 52 to lower voltage withstand characteristics or to cause electrical discharge or pollution or a phosphor surface. Although such disadvantage may be reduced by using spring conductors 52 with a weaker force of bias, use of spring conductors with too weak a force of bias leads to reduced resistance against vibrations to detract from the function of the spring conductors in supporting the electron gun 51.
In addition, the operation of welding each of the spring conductors 52 to the fourth grid G.sub.4 is laborious and presents problems in production costs due to an increased number of process steps.